Bio:Shortly before the events of Crisis on Infinite Earths Superman of Earth 1 visited Earth-Prime (DC's fancy name for "the real world"), where all the characters of the DCU live...in the pages of comic books published by DC. One night, the Clark Kent of that world (okay, our world) is attending a costume party, dressed as Superboy. For reasons somewhat obscure, at that moment his powers (as a the Kryptonian son of a supposedly real-life Jor-El) manifest themselves. He returns with Superman to Earth-1, where he has a brief existence before and during Crisis. At the conclusion of Crisis, he goes with Superman I, Lois Lane-Kent I to live in another dimension from which he can never return.

(How or why there can BE another dimension after DC had just taken a year to explain how they were collapsing all the dimensions into a single reality are questions for a more mentally agile scholar than me.)